how do you wipe data and cache?

[dolfanpete]

And what does doing this do? I have rom manager and am trying to install bugless beast v.04 for newly updated 2.2 it says to be sure to wipe data and cache. Helppppppp

 

[cromo8]

if you are downloading from rom manager at the end of the download there will be an option to wipe data and cache, if you are doing clockwork then before the update.zip option there is an option to wide data and cache above it